Trigeminal neuralgia and multiple sclerosis

1-2 per cent of the patients suffering from multiple sclerosis (MS) are aff licted with trigeminal neuralgia and 2 - 8 per cent vice-versa. Thus, comor bidity of MS and TN is obvious. Commonly a patch with demyelination or late r on a glial plaque located in the pontine entry zone of the trigeminal roo t is responsible for the manifestation of TN. Therefore, Jannetta's operati on with microvascular decompression of the trigeminal root is ineffective i n these cases. Using carbamacepine as first choice and phenytoine as second choice in the treatment of MS-depending TN caution is necessary because hi gher daily dosage might aggravate nystagmus and other cerebellar MS-symptom s.